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From: Kristjan Mustkivi <sonicmonkey@gmail.com>
Date: Tue, 21 Apr 2026 11:33:53 +0300
Message-ID: 
 <CAOQPKatLGcDMJ+tFpRqO-NWfs8xgN3v692CmxrV9MMG=qZn1Hg@mail.gmail.com>
Subject: Re: table bloat very fast and free space can not be reused
To: Rick Otten <rottenwindfish@gmail.com>
Cc: James Pang <jamespang886@gmail.com>,
 pgsql-performance@lists.postgresql.org
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On Mon, Apr 20, 2026 at 5:39=E2=80=AFPM Rick Otten <rottenwindfish@gmail.co=
m> wrote:
>
>  Which design is an antipattern?  Using json for volatile data sets or un=
logging the table?

For us, a large (i.e spilling over to TOAST) json blob in a table
where this json blob (or text, does not matter) gets very frequent
(hundreds and thousands of) updates per minute.

> Does `pg_repack` help?  I know it probably isn't practical to run it ever=
y couple of days.  It also can sometimes causes headaches when repacking a =
table with a ton of logical replication activity, but it might be a tool to=
 consider if you haven't already.   If you can partition the table with the=
 crazy amount of json changes, you don't have to repack all the partitions,=
 you might be able to repack just the older ones with the worst bloat.

This feels like a complexity I personally would like to avoid. Far
more preferable is to get rid of the json. Split the large json into a
normalized table design based on the most useful/frequent patterns.

Br,
--=20
Kristjan Mustkivi

Email: kristjan.mustkivi@gmail.com